Heat exchange apparatus



g- 1937- R. M. HANNY 2,091,757

HEAT EXCHANGE APPARATUS Filed May 16, 1935 0 GOOOOQQQGOGOO G mssssssINVENTOR l RUPEETM.HANNY ATTORNEY Patented Aug. 31,- 1937 UNITED STATESPATENT OFFICE HEAT EXCHANGE APPARATUS Pennsylvania Application May 16,1935, Serial No. 21,823

10 Claims.

My invention relates to heat exchange apparatus, more particularly toheat exchange apparatus in which one fluid is at least partiallyvaporized, and it has for an object to provide improved apparatus.

A further object is to improve the heat transfer rate of such apparatus.

The present invention constitutes a modification of the inventionclaimed in the patent of John P. Rathbun, Patent No. 2,084,743, issuedJune 22, 1937. f

The heat exchanger of the present invention comprises a shell or othervessel in'which there are disposed heating elements, such as tubescontaining heating fluid. Bafiies are arranged to provide a plurality ofpassages through which the liquid flows upwardly in contact with theheating elements to be heated thereby, Other passages are provided forconveying all the liquid rising to the upper end of one hea'tingpassage, out of contact with heating elements, to the lower end of thenext heating passage. With this arrangement, the liquid flows throughthe several heating passages in series without recirculation in theindividual passages. The vapor formed in each heating passage is removedthrough the upper portion of the shell. The natural convection currentsare thereby utilized to provide maximum flow and heat transfer.

The above and other objects are efiected by my invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawing, forming a part of this application, inwhich:

Fig. 1 is a longitudinal vertical section through a heat exchangerembodying the present invention;

Figs. 2, 3 and 4 are sectional views taken on the lines IIII, IIIIII andIVIV of Fig. 1;

Fig. 5 is a broken perspective view showing the 'baflle arrangement; and

Figure 6 is a longitudinal ing a modification.

Referring to the drawing in detail, I show a vertical section showheatexchanger comprising a cylindrical shell I0 which may have an integralclosure at one end, as shown at II. vided at the other end of the shell.The shell I0 contains tubes I3 and I4 for circulating heating fluid, thetubes being arranged in a group or nest in the lower portion of theshell, that is, somewhat below the top of the shell as shown on thedrawing. The tubes are preferably formed into a removable tube bundle,being connected at one end to a stationary tube sheet I5, whose edgesare A removable head I2 is proshown in Figs. 3 and 4. The curved plates32 secured between flanges I6 and Il, securing the head I2 to the shellI8, and secured at the other end to a floating tube sheet I8. Thefloating tube sheet I8 carries a floatinghead or cover I9,

, that any suitable heating fluid may be used, for

example, steam may be used, as contemplated by the illustratedembodiment, in which case the tubes I3 may be greater in number than thetubes I4. The steam gives up its latent heat in the tubes I3 and thetubes I 4 serve primarily for returning the condensate to the header I2.

The shell III is formed with a liquid inlet 26, in this case disposed inthe lower portion of the shell at the end adjacent the head I2. It isformed with a vapor outlet 21 in the top thereof, and with a liquidoutlet 28 in the bottom at the end opposite the inlet 26. A secondliquid outlet 280. may be provided, if desired.

The lower portion of the-shell containing the tube nest is divided intoa plurality of compartments 29 by partitions 30. The partitions alsoserve as tube support plates, having openings through which'the tubesare extended. Each partition is somewhat more than semicircular inshape, the upper edge .being disposed a short distance above the top ofthe tube nest. Each partition 30 has a rectangular opening 3| adjacentthe bottom thereof, as shown on the drawing. The tube nest is spacedfrom the cylindrical wall of the shell, as may be seen in Figs. 3 and 4,and in each of the compartments 29 other than the first, I provide abaflle structure extending about the sides and bottom of the tube nest,

thereby providing downwardly-extending passages 35 onopposite sides ofthe tube nest. This baflle structure comprises curved plates 32 onopposite sides of the tube nest, the upper edges being at the level ofthe top of the tube nest and the lower edges being horizontally spaced,as

have extensions 33 adjacent the lower edges which are bent to extenddownwardly. The lower edges of these extensions are inclined, as may beseen in Fig. l, and a plate 34 is secured to said inclined edges, as bywelding. The extensions 33 for conveying liquid from the opening 3| ofthe and the plate 34 together form a passage or flume partition on theupstream side (on the left in Fig. 1) to the lower portion of the tubespace. The battle structure in each compartment may be secured in anysuitable manner, for example, it may be removably secured to thepartitions 3!! by being bolted as shown at 36. The baflle structure inthe first compartment 29 is modified to provide communication betweenthe tube space and the liquid inlet 26. It comprises a single baflie 31extending about the bottom and sides and having a conduit portion 38extending through the passage 35 to the inlet 26.

The Shell is preferably formed with a transversely-extending weir 39adjacent the floating head l9, thereby insuring that the tubes arecompletely submerged at all times and also providing a storage chamber4| between the weir and the closed end ll.

Operation be vaporized and separated from the other, is,

admitted to the shell through the inlet 26 and the conduit 38 to thetube space of the first compartment 29. As it flows upwardly therein, itis through the liquid outlet 28.

heated by contact with the tubes, thereby vaporizing a portion of thevolatile component. As it reaches the top of the tube nest, thevaporized portion is liberated and passes into the vapor spaceconstituted by the upper portion of the shell above the tube nest. Theliquid spills over the upper edges of the curved baflle and passesdownwardly through the passages 35 to the bottom thereof. The liquidthen passes into the tube space of the next compartment 29 through theopening 3| in the intervening partition 30, passing to the right as seenin Fig. 1. The liquid is conveyed by the 'fiume formed by-the extensions33 and the plate 34 to the tube nest, in which it again rises and isheated as it rises. This cycle of operation is'repeated in each of thecompartments until it reaches the last compartment 29, from which itspills over the top of the tube sheet l8 and the top of the weir 39 intothe storage chamber 4|. From the latter, it is drawn off If it isdesired to draw ofi some liquid before the volatile component thereofhas been entirely vaporized, the liquid outlet 28a may be used for thispurpose. The vaporized portion of the fluid is withdrawn from the vaporspace in the upper portion of the shell through the vapor outlet 21.

In the present embodiment, the entire flow of liquid rising to the topof the tube space in each compartment is conveyed through the passages35 and the opening 3! to the next compartment, so that it does notrecirculate in any one compartment. The liquid passes through thecompartments in series, as will be apparent from the above description.The above arrangement makes use of the natural convection currents whichare set up by the heating of the liquid, which currents are added to thegravity flow current from the liquid inlet end to the liquid outlet endof the shell. Furthermore, the static head on the liquid is repeatedlyreduced as it reaches the top of the tube nest so that the lighterfractions may be liberated. Also, the improved flow currents providedprevent the accumulation of vapor bubbles on the submerged hot surfacesof the tubes.

Theabove apparatus is of particular utility in manufacturing petroleumproducts, in which the liquid admitted to the inlet 26 containsconstituents of varying boiling points. The constituents of lowerboiling points, known as the lighter fractions are vaporized first, andthen constituents of higher boiling-points are successively vaporized asthe liquid flows from the inlet end of the shell to the outlet end. Inthis field, the apparatus is knownas a reboiler.

In some cases, it may be desirable to separately remove the vapors ofvarying boiling points. In this case, partitions 30a may be extended tothe top of the shell, as shown in Fig. 6, in which case there is aseparate vapor space in the top of each compartment 29. is provided atthe top of each compartment. In other respects, the apparatus shown inFig. 6 is the same as that shown in Figs. 1 to 5.

While I have shown' my invention in several forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are imposed by the prior art or as are setforth in the appended claims.

What I claim is:

1. In heat exchange apparatus, the combination of a shell, meansproviding heating passages for upward flow of liquid, heating elementsin A separate vapor outlet 21a said passages, means for conveying allthe liquid rising to the upper portion of one heating passage, out ofcontact with heating elements, to the lower end of the next heatingpassage, the liquid flowing through said one heating passage only oncebefore it is conveyed to the next heating passage by said last-mentionedmeans, and means for removing vapor from the upper end of each heatingpassage.

2. In heat exchange apparatus, the combination of a shell having aliquid inlet and having a vapor outlet in the upper portion thereof,means providing a plurality of compartments in the lower portion of saidshell, heating elements in said compartments, means in one compartmentfor conveying the entire liquid stream upwardly only once in contactwith the heating elements in said compartment and then downwardlysubstantially out of contact with heating elements to the lower portionof the next compartment, the upper portion of said shell providing avapor space affording communication between said one compartment andsaid vapor outlet.

3. In heat exchange apparatus, the combination of a shell;transversepartitions in said shell dividing the lower portion thereof into aplurality of compartments, the upper portion of the tion of a shell,transverse partitions in the lower portion of the shell dividing thesame into a plurality of compartments, a group of tubes in the shellextending throug'h the several compartments, and means for conveying allthe liquid rising to the upper portion of one compartment out of contactwith the tubes to the lower portion of the next compartment withoutrecirculating the same through said one compartment, the upper portionof the interior of the shell constituting a vapor space communicatingwith the several compartments at ,the top thereof.

' 5. In heat exhange apparatus, the combination of a shell, a group oftubes therein, bailles disposed transversely of the tubes and providinga plurality of compartments, other baflles in the compartments providingfirst vertical passages through which the tubes extend and secondvertical passages substantially without tubes, the vertical passages ineach compartment being in communication at the upper ends whereby liquid7 l5 flows upwardly in the first passage only once and then downwardlyin the second passage, and means for conveying liquid from the lower endoi the second passage of each of a plurality of successive compartmentsto the lower end of the first passage of the next] compartment, saidmeans being sealed oil from the first passage 01' the precedingcompartment.

6. In heat exchange apparatus, the combination of a longitudinal shell,a group oi tubes 26 disposed longitudinally in the lower portion of saidshell in spaced relation to the longitudinal wall thereof, a pluralityof partitions extending transversely of the tubes for dividing the lowerportion of the shell into a plurality of compart- 30 ments, baflle meansin each compartment disposed partly around the tube bundle to provide apassage between said wall and tubes out of contact with the tubes, theupper edge of said baiile means being disposed below the upper edge 85oi the partitions to permit liquid to spill thereover, and means forconveying liquid from the lower end of one passage to the lower portionof the tube space of the next compartment, all of the liquid rising tothe top of the tube space of one compartment being conveyed, the firsttime that it rises to the top, through the passage and last-mentionedmeans to the next compartment.

7. In heat exchange apparatus, the combination 01' a shell, a group oftubes in the lower portion of the shell, partitions extendingtransversely of the tubes and providing a plurality of compartments inthe lower portion of the shell, each partition having an openingadjacent the bottom thereof, baiile means disposed about the sides andbottom oi the group of tubes in each compartment to divide thecompartment into a tube space and passages substantially devoid'oitubes, the upper edges of said bailie means being dis-\ 5 posed to causeliquid rising through the tube space to spill over into said passages,the lower portion of the bame means of one compartment being formed toprovide a fiume for conveying liquid from the previous compartmentthrough 80 the opening in the intervening partition to the lower end orthe tube space and to conveythe liquid flowing downwardly in thepassages through the opening in the partition on the opposite side ofthe compartment into the lower 65 portion of the tube space in the nextcompart men 8. In a heat exchanger, the combination of a shell, a'bundleof heating tubes disposed horizontally therein, said bundle of tubesbeing arranged to provide space substantially devoid of tubes extendingfrom the top to the bottom of the tube bundle, a baille extendinglongitudinally along the side of the tube bundle and dividing the tubecontaining space from the space devoid of tubes, baflies extendingtransversely of the tubes and dividing the tube containing space into apluraliity of heating passages, and baiiie means in the space devoid oftubes providing a passage arranged to convey liquid from the top or oneheating passage to the bottom of the next heating passage, saidlast-mentioned passage constituting the only outlet for liquid rising tothe top of said one heating passage so that the liquid flows but oncetherethrough.

9. In a heat exchanger, the combination of an elongated shell having aliquid inlet and a liquid outlet, a bundle of heating tubes disposedhorizontally and longitudinally therein, said bundle of tubes beingarranged to provide a space sub, stantially devoid of tubes extendingfrom the top .to the bottom of the tube bundle, a baflle extendinglongitudinally along the side of the tube bundle and dividing the tubecontaining space from the space devoid of tubes, baiiies extendingtransversely of the tubes and dividing the tube containing space into aplurality of heating passages through which the liquid flowssuccessively from said liquid inlet to saidliquid outlet, baiiles in thespace devoid of tubes dividing the sameinto a plurality of passages eacharranged to convey liquid from the top of one heating passage to thebottom of the next heating passage, each of the last-mentioned passagesconstituting the only outlet for liquid rising to the top or the saidone heating passage so that liquid flows but once through each heatingpassage, and means for removing the vapor from the liquid at the upperend of each heating space.

10. In a heat exchanger, the combination of a shell, a bundle of heatingtubes disposed horizontally therein, said bundle of tubes being arrangedto provide space within the shell devoid oi tubes extending from the topto the bottom of the tube bundle, partitions extending transversely ofthe tubes and dividing the tube-containing space into a plurality ofheating passages, the top of the tube bundle and the upper edges of saidtransverse partitions being spaced from the top of the shell to providea vapor space in the upper portion of the shell for receiving vapor fromthe several heating passages, and partition means providing passages insaid space devoid of tubes for conveying liquid from the top of oneheating passage to the bottom of the next heating passage, at least aportion of the upper edges of said partition means being disposed belowthe upper edges of said transverse partitions, said partition meanspreventing recirculation of liquid through a heating passage throughwhich it has already flowed, and said shell having a. liquid inletcommunicating with the lower end of the first heating passage and avapor outlet communicating with said vapor space.

- RUPERT M. HANNY.

